Synthesis and Characterization of Nanocrystalline (Zr₀.₈₄Y₀.₁₆)O₁.₉₂-(Ce₀.₈₅Sm₀.₁₅)O₁.₉₂₅ Heterophase Thin Films

A new type of nanocrystalline samarium-doped-ceria/yttrium-stabilized-zirconia (SDC/YSZ) heterophase thin film electrolytes was synthesized on MgO and Si substrates by spin coating and thermal treatment of SDC-nanoparticle-incorporated polymeric precursors. In the heterophase films, SDC nanoparticles were uniformly dispersed in a nanocrystalline YSZ matrix. The heterophase structure was stable when fired in air at temperatures up to 850 °C. The nanocrystalline heterophase thin films exhibited electrical conductivities significantly higher than that of the phase-pure YSZ and SDC nanocrystalline thin films at reduced temperatures. The effects of SDC grain size and volume fraction on the electrical conductivity of the heterophase films were also studied

Phylogeny of European Dolichopus and Gymnopternus (Diptera: Dolichopodidae) and the significance of morphological characters inferred from molecular data

Dolichopodidae (over 6000 described species in more than 200 genera) is one of the most speciose families of Diptera. Males of many dolichopodid species, including Dolichopus, feature conspicuous ornaments (Male Secondary Sexual Characters) that are used during courtship. Next to these MSSCs, every identification key to Dolichopus primarily uses colour characters (postocular bristles; femora) of unknown phylogenetic relevance. The phylogeny of Dolichopodidae has rarely been investigated, especially at the species level, and molecular data were hardly ever involved. We inferred phylogenetic relationships among 45 species (57 samples) of the subfamily Dolichopodinae on the basis of 32 morphological and 1415 nucleotide characters (810 for COI, 605 for Cyt-b). The monophyly of Dolichopus and Gymnopternus as well as the separate systematic position of Ethiromyia chalybea were supported in all analyses, confirming recent findings by other authors based purely on morphology. Within Dolichopus, stable species groups could be assigned to four distinct categories on the basis of their statistical support in 7 phylogenetic analyses: (i) clades significantly supported in all analyses, (ii) clades supported in trees based on DNA and combined data, but only partly in morphological trees, (iii) clades significantly supported in trees based on DNA and combined data, but not in morphological trees, and (iv)clades consistently supported only in morphological trees. The phylogeny generated here provides a better understanding of the phylogenetic relevance of some debated morphological characters used for species and species-group characterizations in the most commonly used identification keys. In this respect, postocular bristle colour proved of little phylogenetic relevance since every group with species featuring black bristles also included species with partly yellow bristles. Entirely or partly infuscated femora explained the nodes of three stable species groups and even revealed an incorrect polarity of this morphological character in three species. Four of 6 complex MSSCs and 5 of 8 more common MSSCs were found consistently in further species groups

Legs of deception: disagreement between molecular markers and morphology of long-legged flies (Diptera, Dolichopodidae)

Conflicting hypotheses in phylogenetics and systematics, generated by different data sets (e.g. morphological versus molecular), are common in biology. The clarification of such instances may allow understanding general mechanisms involved in the speciation process in an evolutionary light. Here, we present and discuss the case of the Dolichopus plumipes species group in the long-legged flies, Dolichopodidae. A phylogenetic survey was performed based on both morphological and molecular data. The full data set comprises 31 morphological characters and 2252 molecular characters (mitochondrial - COI: 810; 12S: 343; 16S: 514; nuclear - ITS2: 585) of 49 different species, represented by 82 specimens. The molecular phylogenetic analysis revealed a clade (composed by the species D. plumipes, Dolichopus wahlbergi, Dolichopus polleti, Dolichopus simplex, and Dolichopus nigricornis) that disagrees with the traditional morphological view based on external characters. In particular, specimens of the species D. plumipes and D. simplex were indistinguishable with the molecular markers used here. Yet, we still consider D. plumipes and D. simplex as two distinct taxa and provide explanatory hypotheses on the evolutionary background. The conspicuous male secondary sexual characters (present in plumipes but not in simplex) are key factors in sexual selection and their presumably rapid reduction in D. simplex is thought to be of main importance for the explanation of the speciation process. The plumipes-simplex case may therefore be viewed as a paradigmatic illustration showing that a better integration of the molecular and morphological approaches is needed to understand and clarify the, in some cases, complex systematics and phylogeny of organisms.Zusammenfassung Widerspruchliche Hypothesen in Phylogenie und Systematik durch die Verwendung unterschiedlicher Datensatze (z.B. morphologische und molekulare Daten) sind keine Seltenheit in der Biologie. Die schlussige Klarung solcher Sachverhalte erlaubt vielfach ein Verstandnis grundlegender evolutiver Mechanismen der Artbildung. Hier prasentieren und diskutieren wir einen solchen Fall anhand der Dolichopus plumipes Artengruppe der Langbeinfliegen, Dolichopodidae. Eine phylogenetische Analyse morphologischer und molekularer Daten wurde durchgefuhrt. Der Datensatz umfasst 31 morphologische und 2252 molekulare Merkmale (mitochondrial: COI: 810; 12S: 343; 16S: 514; nuklear: ITS2: 585) von 49 Arten, welche in 82 Individuen vertreten sind. Die Analyse der molekularen Daten ergab eine Gruppe (bestehend aus D. plumipes, D. wahlbergi, D. polleti, D. simplex, und D. nigricornis), welche sich nicht mit der traditionellen morphologischen Sicht deckt. Als Uberraschung waren Individuen der Arten D. plumipes und D. simplex mit den verwendeten molekularen Markern ununterscheidbar. Wir betrachten D. plumipes und D. simplex dennoch weiterhin als unterschiedliche Taxa und stellen erklarende Hypothesen zum evolutiven Hintergrund dazu vor. Die auffalligen sekundaren mannlichen Geschlechtsmerkmale (vorhanden bei plumipes, fehlend jedoch bei simplex) sind Schlusselfaktoren der sexuellen Selektion. Damit kommt der vermutlich schnellen Reduktion dieser Merkmale bei D. simplex gro beta e Bedeutung fur die Erklarung des Artbildungsprozesses zu. Der plumipes-simplex-Fall soll auch als paradigmatische Illustration einer starkeren Integration von molekularen und morphologischen Ansatzen dienen, was in einigen Fallen unverzichtbar ist fur das Verstandnis komplexer Systematik und Phylogenie von Organismen